Field of the Invention
The invention relates to an implantable actuating mechanism for an implant which can be switched between two stable states or settings, with a support element and with a spring-activated actuating element which can be moved relative to the support element.
An actuating mechanism of this type for a closure device for natural or artificial tubular organs of the body is known, for example, from European patent application EP-A-19 644. A cuff made of a biocompatible foreign material which can be placed around the organ contains a pressure medium and cuts off the tubular organ when pressure medium is forced into the cuff from a likewise implanted pressure-medium container. The compressible pressure-medium container is provided with the actuating mechanism which on the one hand has a heart-shaped guide track and on the other hand has a pin moving therein, so that both the compressed and the relaxed positions are stable. The disadvantages associated with the prior art device lie in the use of a pressure fluid, the lines which have to be provided, the risk of leakage, and the need for an implanted storage container, etc.
To prevent urinary incontinence, European patent application EP-A-639,355 discloses a band sling which is made of a biocompatible foreign material and engages under the urethra, the ends of the band being fixed at a higher point in the body, and the central area of the band sling representing a chamber that can be filled with fluid. The amount of fluid introduced determines the height of the urethra and thus likewise can be adjusted. The European document EP 639,355 also indicates that fascias have already been used for forming a band sling, which fascias are fixed in the body. However, subsequent correction necessitated by changes is not easily possible.
It is accordingly an object of the invention to provide an implantable actuating mechanism, which overcomes the above-mentioned disadvantages of the heretofore-known devices and methods of this general type and which mechanism, without any hydraulic system, actuates an implant that can be switched between two states or settings, and in particular prevents urinary incontinence.
With the foregoing and other objects in view there is provided, in accordance with the invention, an implantable actuating mechanism for an implant which can be switched between two stable settings, comprising:
a support element;
a spring-biased actuating element movably disposed relative to the support element, the actuating element extending through the support element and having an activation part, on a side opposite the support element, for triggering a change between the two stable settings of the implant.
In other words, the objects of the invention are attained in the actuating element is guided through the support element and, on the other side of the support element, has an activation part which triggers a switch between the two stable settings of the implant.
Depending on the intended use, the actuating mechanism is fitted at a suitable position in the body so that the actuating element can be reached through the skin and can be moved in the support element by pressure from outside. The activation part projecting inward from the support element thus executes a linear reciprocating motion which is transmitted by suitable means to the implant which is to be switched.
In accordance with a preferred embodiment of the actuating mechanism, the activation part has a holder for the two ends of a fascia. Such a holder involves in particular a combination of form closure (form lock) and frictional closure (force lock) in order to guarantee many years of stable connection. The activation part has two or three bearing plates or the like between which the fascia ends are held, elevations and corresponding depressions being provided for the form closure. The elevations can on the one hand be pyramid-shaped and have points sticking into the fascia, and on the other hand they can form cylindrical pins which engage in bores or openings. For the additional frictional closure, an undercut and resilient locking stud can also be provided which locks in one of the openings and clamps the fascia ends.
That is, the activation part has a holder for the two ends of a fascia engaging under a tubular organ. In accordance with an added feature of the invention, the holder includes a first bearing plate and a second, opposite bearing plate, and the first and second bearing plates are formed with corresponding elevations and depressions.
There is thus provided, in accordance with the invention, an implantable device for preventing urinary incontinence in a patient. The device comprises a fascia for engaging under the urethra and configured to be moved to an upper position to lift the urethral attachment, the fascia having two ends connected to the actuating mechanism as outlined above to be fixed on the pubic bone of the patient, whereby at least the upper position of the fascia is defined by one of the stable settings of the actuating element.
With the above and other objects in view there is also provided, in accordance with the invention, an implantable actuating mechanism for an implant to be switched between two stable settings, comprising:
a mounting plate to be fixed to a bone of a patient;
a support element;
a spring-activated actuating element movably disposed relative to the support element and projecting from one side through the support element to an opposite side; and
an activation part on the opposite side of the support element for triggering a switch between the two stable settings of the implant, whereby the actuating mechanism is switchable between the two stable settings.
Similarly, there is provided an implantable device for preventing urinary incontinence in a patient, comprising:
a fascia configured to engage under the patient""s urethra and to be moved from a lower position to an upper position for lifting a urethral attachment, the fascia having two ends;
an actuating mechanism as outlined above configured to be fixed to the patient""s pubic bone;
wherein the two ends of the fascia are connected to the holder of the actuating mechanism and the upper and lower positions of the fascia are defined by the two stable settings of the actuating element.
For holding the actuating mechanism in the body, the invention provides in particular that the support element has a mounting plate for bearing or fixing on a bone.
The length of the activation element extending beyond the support element can be adjusted by means of a setscrew which can be operated at the pressure surface of the actuating element and which is accessible through the skin.
In order to achieve a better adaptation to the conditions, the activation part can be articulated on the actuating element. In another configuration, the support element can have a curved end area through which a cable line is guided which connects the activation part to the actuating part. To screen off the articulation or the cable line, a bellows is preferably provided between the support element and the activation part.
For closing and opening the urethra actively, i.e. in a way that can be influenced from outside, by lifting and lowering a fascia engaging under the urethra, which effects either a change in the vesico-urethral angle or, by lifting the urethra, clamps it off, the invention provides that the two ends of the fascia are connected to an actuating mechanism which can be fixed on the pubic bone, and both the upper closure position and the lower opening position of the fascia are in each case defined by one of the two stable settings of the actuating element.
In a further preferred embodiment of the actuating mechanism, the activation part is assigned to an electrical switching contact. The switching contact is used to close or interrupt a circuit of an implant, the energy being supplied from a current reservoir arranged in the actuating mechanism. The current reservoir can in particular be charged without contact from the outside. If, for example, striated or smooth muscle is grafted to the urethra through muscle flap transfer or as a free muscle transplant, an incorrectly functioning or nonfunctioning urethral sphincter muscle can be replaced by a muscle which is supplied with blood and, after a transition time, is reinnervated. This sphincter replacement muscle is excited to contraction by a high-frequency energy impulse transmitter, this contraction closing the urethra and preventing involuntary discharge of urine (incontinence). The impulse transmitter arranged in the body can be switched on and off by the actuating mechanism. In the switched-off state, the sphincter replacement muscle relaxes and thus permits deliberate voiding of the bladder by the patient. When the switching contact is closed directly after the bladder has been emptied, renewed contraction of the sphincter replacement muscle takes place and this allows the bladder to be filled with urine flowing from the kidneys, without inadvertent discharge of urine to the outside. This principle can also be applied to all other functions concerned with closing body openings and body passages, for example the anal sphincter, the esophageal sphincter, etc.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in an implantable actuating mechanism, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.